1. Field of the Invention
The present invention relates to a backup system for distributed systems at remote locations.
2. Description of the Related Art
As an example, FIG. 13 shows a backup system for remote system disclosed in Unexamined Japanese Patent Publication No. 11-39273. In FIG. 13, a computer 5 for performing a general task and a backup computer 6 for performing backup are provided. The computer 5 is composed of an on-line processing unit 50, a file transmission controller 51, a file 8 for backup, and a journal file 9. The backup computer 6 is composed of a file reception controller 60, a data recovery processing unit 61, a file 100 for backup, and a journal file 110 for reception. The computer 5 and the backup computer 6 are connected by a backup line 7. A terminal 130 is connected to the computer 5 and the backup computer 6, through a line 71 and a backup line 72.
Operations of the backup system shown in FIG. 13 will now be explained. The backup computer 6 stores an updated image history of the file 100 for backup, in the journal file 110 for reception. In the event that the computer 5 becomes unusable because of a fault, the backup computer 6 recovers a file based on the journal file 110 for reception, and continues the tasks as a backup of the computer 5.
In the conventional backup system, as described above, it is needed to prepare one backup computer for one computer generally used. Then, the conventional backup system has a drawback that a large-scale backup system is necessary for performing backup for a large-scale system.